Hydrogenation catalysts on charcoal in guard chamber for removing metals from petroleum residua



United States Patent O 3,546,103 HYDROGENATION CATALYSTS ON CHARCOAL INGUARD CHAMBER FOR REMOVING METALS FROM PETROLEUM RESIDUA Glen P. Hamner,Baton Rouge, and Ralph B. Mason, Denham Springs, La., assiguors to EssoResearch and Engineering Company, a corporation of Delaware No Drawing.Filed Feb. 3, 1969, Ser. No. 796,213 Int. Cl. Cg 23/02, 31/14 U.S. Cl.208-211 9 Claims ABSTRACT OF THE DISCLOSURE Metals and coke precursorsare removed from petroleum residua prior to hydrodesulfurization bycontacting the residua with a hydrodesulfurization catalyst supported oncharcoal or activated carbon so that the metals may be easily recoveredby gasifying or burning the carbon base.

BACKGROUND OF THE INVENTION This invention relates to a method for theremoval of metals and coke precursors from heavy feeds to ahydrodesulfurization process.

The higher boiling fractions of crude petroleum often contain traces ofvanadium, nickel and other metals which cause rapid deactivation ofsulfur resistant catalysts used in the hydrodesulfurization of suchfractions. This is particularly true of residuum fractions as a resultof which it has not been practical to refine such fractions by acatalytic hydrodesulfurization process.

It has previously been suggested that metals be removed from feeds to ahydrodesulfurization process by first contacting the feedstock withbauxite in the presence or absence of hydrogen under conditions oftemperature and pressure such that the metals are deposited on thebauxite as described in U.S. Pats. 2,687,985, filed Jan. 22, 1953, toPorter and Purdy and 2,769,758 filed Mar. 13, 1952, to Porter and Isitt.The use of titania on alumina for the same purpose is described in U.S.Pat. 2,730,487 filed July 1, 1953, to Porter and Purdy.

It is also known to remove asphaltenes as well as metals from a reducedcrude prior to desulfurizing the same, by contacting the reduced crudein the presence of hydrogen with a catalyst similar to that used in thesubsequent desulfurization stage or with an essentially inertparticulate contact material such as tabular alumina, electrician beads,extruded alumina or a low activity catalyst as described in U.S. Pat.3,362,901 to Szeppe et al., filed I an. 11, 1966, and issued Jan. 9,1968.

While the above processes are successful in removing metals from heavypetroleum fractions, nevertheless it has been found somewhat diificultto remove the metals from the bauxite, alumina or other supports used inthe preliminary treating zone.

SUMMARY OF THE INVENTION In accordance with the present invention theabove disadvantages are overcome by first contacting the feedstock in aguard chamber containing a hydrodesulfurization catalyst supported on acharcoal or activated carbon base at elevated temperature and pressurein the presence of hydrogen so that a considerable proportion of themetals and coke precursors are deposited thereon and thereafter passingthe thus treated feedstock to a hydrodesulfurization zone undergenerally more severe conditions than prevails in the first stagewhereby the activity of the catalyst is increased and the catalyst lifeis extended because of reduced metal deposition. In one embodiment thecharcoal base can be easily removed by burning or steam gasification toform desirable gas products leaving 3,546,103 Patented Dec. 8, 1970DESCRIPTION OF THE PREFERRED EMBODIMENTS The charcoal or activatedcarbon base suitable for use in this invention may be any solid type ofcarbon capable of supporting metallic catalyst. However it is preferredto use activated carbon which is made by the destructive distillation ofcarbonaceous material under controlled conditions. The specific area ofsuch a carbon may range from 600 to 2000 square meters per gram.

Any type of sulfactive hydrogenation catalyst may be used in conjunctionwith the charcoal or activated carbon base. Suitable catalysts includeone or more of the oxides or sulfides of a metal of Group VIII incombination with metals of Group II-B and VI-B, such as Ni-W, Ni-Mo,Co-Mo, Co-W, Zn-Mo, Zn-W or mixtures thereof. A typical catalystcontains about 0.1 to 20% by weight of a Group VIII metal such as nickeland about 0.1 to 20% by weight of a Group VI-B metal such as tungsten.

The reaction conditions used in the first stage can vary over wideranges depending on the particular feed. Generally the conditionsinclude pressures of from about 500 to 1500 p.s.i.g., a temperature ofabout 650 to 950 F., a feed rate of 0.5 to 20 volumes of feed per volumeof catalyst per hour (v./v./hr.) and 1000 to 10,000 s.c.f. per barrel ofhydrogen.

The subsequent hydrodesulfurization reaction is accomplished overcatalysts which are preferably more active than those used for thepreliminary treatment. The active metallic components in the catalystare a Group VI-B oxide or sulfide, specifically an oxide or sulfide ofmolybdenum, tungsten, or their mixtures and a Group VIII metal oxide orsulfide, specifically an oxide or sulfide of nickel or cobalt. Suitablecatalysts consist of 1 to 15 wt. percent of nickel or cobalt (as oxide)preferably 2 to 10 wt. percent, 5 to 25 wt. percent of tungsten ormolybdenum (as oxide), preferably 10 to 20 wt. percent supported onalumina, the alumina preferably containing 1 to 6 wt. percent of silica.A particularly suitable catalyst consists of 3.5 wt. percent of C00" and12.5 wt. percent M00 on alumina containing about 2.0 wt. percent silicaand having a maximum surface area in pores having a diameter of 30 to 70A. as described in application Ser. No. 648,604 filed June 26, 1967,which was issued as U.S. Patent 3,509,044 on April 28, 1970, to Adamsand House and the subject matter of which is incorporated herein byreference.

The reaction conditions in the hydrodesulfurization step may rangebetween 500-825 F., preferably 650-800, 500-2500 p.s.i.g., preferably800-1800 p.s.i.g., a space velocity of 0.2 to 5.0 v./v./hr., preferably0.5-2.0, and a hydrogen rate of 500-7500 s.c.f. per barrel, preferably1000-5000.

The feed stock is preferably a petroleum residium 30 to of which boilsabove 900 F. and which is obtained from crude oils by distillation ortreating or by some other type of separation. The residuum may be ablend of high boiling materials such as atmospheric bottoms, vacuumbottoms, deasphalted oil visbreaker bottoms, gas oil cuts and the like.All of these materials contain about 25 p.p.m. or more each of nickel orvanadium measured as the oxides NiO and V 0 The following example isincluded to illustrate the effectiveness of the instant process for thepreliminary 3 treatment of petroleum residuum prior tohydrodesulfurization thereof without limiting the same.

EXAMPLE Three runs were carried out using West Texas residuum andBachaquero residuum as feed. In each case the feed was passed over anickel-tungsten catalyst (2.3% Ni and 11.4% W) on activated charcoal ata temperature of 800 F., 1000 p.s.i.g., 1 v./v./hr. at a 5000 s.c.f. ofH per barrel gas rate. The metals were recovered by burning the charcoaland recovering the metals from the ash.

The following data were obtained.

Bacliaquero West Texas Feed 400 F. Feed Run No Prod. Distr Feed F 08d COand CO2 0.8 0.4 0.5 1.7 1.1 1.9 0.7 0.7 0.8 100 97. 0 97. 8 100 96. 8

ct on Gravity, API 18. 3 29. 3 25. 5 15. 2 24. 7 Sulfur, wt. percent 2.2 0. 0. 64 2. 4 0. 55 6. 0 0. 8 2. 5 10. 5 3. 4 24 l 1 400 56 12 1 1 5712 Wt. percent on feed (output basis).

The above data show that metal removal from the pretreatment wasexcellent 1 ppm.) with West Texas residuum and satisfactory with thehigh-metal content Bachaquero residuum 70 p.p.m.). The Conradson carbonlevel of both feed stocks was reduced considerably, indicating theremoval of coke precursors. Furthermore more than 60% desulfurizationwas realized. Substantially complete desulfurization can thus beobtained in a second stage conventional hydrodesulfurization step usingcobalt molybdate catalyst with high catalyst activity maintenance levelfor a long period of time due to the previous removal of metals from thefeed.

The nature of the present invention having thus been fully set forth andspecific examples of the same given, what is claimed as new, useful, andunobvious and desired to be secured by Letters Patent is:

1. A process for the removal of metals and coke precursors from ahydrocarbon residuum containing the same which comprises contacting saidresiduum at 65095 0 E, 500-1500 p.s.i.g., a feed rate of 0.5 to volumesof residuum per volume of catalyst per hour and in the presence of 1000to 10,000 standard cubic feet of hydrogen per barrel of feed and acatalyst comprising an oxide or sulfide of a metal of Group II-B or VI-Btogether with a Group VIII metal on charcoal for a period of time toremove a substantial quantity of the metals.

2. The process of claim 1 in which the catalyst is nickel oxide andtungsten oxide on charcoal.

3. The process of claim 2 in which the catalyst contains 2.3 wt. percentNi and 11.4 wt. percent W.

4. A process for the two-stage treatment of a hydrocarbon residuumcontaining a substantial quantity of metals and coke precursors whichcomprises pretreating said residuum in a first stage with a contactmaterial comprising an oxide or sulfide of a metal of Group II or VI- Btogether with a Group VIII metal on charcoal at 650 950 F., 500-1500p.s.i.g., a feed rate of 0.5 to 20 volumes of feed per volume ofcatalyst per hour and in the presence of 1000 to 10,000 standard cubicfeet of hydrogen per barrel of feed for a period of time to remove asubstantial quantity of the metals and coke precursors and subsequentlycontacting the thus pretreated feed in a second stage with ahydrodesulfurizing catalyst comprising an oxide or sulfide of a GroupVI-B and a Group VIII metal on alumina at a temperature of 500-825 F., apressure of 500-2500 p.s.i.g., a space velocity of 0.2 to 5.0 v./v./hr.and a hydrogen rate of 500-7500 s.c.f./bbl.

5. The process of claim 4 in which the second stage catalyst is 1020 wt.percent molybdenum oxide and 2- 20 wt. percent cobalt oxide on aluminacontaining l-6 wt. percent silica.

6. The process of claim 5 in which the alumina has a maximum surfacearea in pores having a diameter of 30- A.

7. The process of claim 4 in which the metals are removed from the firststage catalyst by burning.

8. The process of claim 4 in which the catalyst of the first stage isregenerated by partial oxidation.

9. The process of claim 4 in which the catalyst of the first stage isregenerated by steam gasification.

References Cited UNITED STATES PATENTS 2,687,985 8/1954 Porter et al208211 2,755,225 7/1956 Porter et al 208-211 2,766,183 10/1956 Porter etal. 208-211 2,987,467 6/1961 Keith et a1. 208-211 3,367,862 2/1968 Masonet al. 208-253 FOREIGN PATENTS 282,513 3/1965 Australia. 682,387 11/1952Great Britain.

DELBERT E. GANTZ, Primary Examiner G. I. CRASANAKIS, Assistant ExaminerUS. Cl. X.R.

